For decades, the most successful equipment users have engaged in up-front assessments of machinery reliability. They allocate time and money for MQA. These seasoned users buy only from competent vendors and establish such competence by pre-procurement MQA endeavors. As part of such assessments, these successful users review documentation showing pump assembly drawings and related indispensable documentation. Potential design weaknesses can be discovered in the course of reviewing dimensionally accurate cross-sectional drawings. Examination and review of cross-sectional drawings is important1-4. There are two compelling reasons to conduct this drawing review during the bid evaluation phase of a project. Firstly, some pump manufacturers may not be interested in responding to user requests for accurate drawings after the order is placed. Secondly, the design weaknesses or vulnerabilities could be significant enough to require extensive redesign. In the latter case, the purchaser may be better off selecting a different pump model2,5.
CHEAP PUMPS ARE RARELY A WISE CHOICE
It is intuitively evident that purchasing the least expensive pump will rarely be the wisest choice for users wishing to achieve long run times and low maintenance outlays. Although a new company may occasionally be able to design and manufacture a better pump, it is not likely that such newcomers will suddenly produce a superior product. Therefore, it would be more reasonable to choose from among the most respected existing manufacturers (i.e., manufacturers that currently enjoy a proven track record).
The first step should involve selecting and inviting only those bidders that meet a number of pre-defined criteria. Here’s the process by which one can determine acceptable vendors for situations demanding high reliability:
- Acceptable vendors must have experience with size, pressure, temperature, flow and service conditions specified.
- Vendors must have proven capability in manufacturing with the chosen metallurgy and fabrication method (e.g., sand casting, weld overlay, etc.)
- Vendors’ “shop loading” must be able to accommodate your order within the required time frame (door-to-door delivery of product).
- Vendors must have implemented satisfactory quality control and must be able to demonstrate a satisfactory on time delivery history over the past several (usually two) years.
- If unionized, a vendor must show there is virtually no risk of labor strife (strikes or work stoppages) while manufacturing of your pumps is in progress.
USE SUPPLEMENTAL SPECIFICATIONS
The second step would be for the owner/purchaser to:
- Specify for low maintenance. As a reliability-focused purchaser, you should realize that selective upgrading of certain components will result in rapid payback. Components that are upgrade candidates have been identified in the literature since the mid 1960s, so be sure to specify those. Review failure statistics for primary failure causes. If bearings are prone to fail, realize that the failure cause may be incorrect lube application or lube contamination. Address these primary failure causes in your specification.
- Evaluate vendor response. Allow exceptions to the specification if they are both well explained and valid.
- Clearly document the equipment design to prevent future failure analysis and troubleshooting efforts from being greatly impeded. Your plant will require pump cross-section views and other documents to effectively manage future repair and troubleshooting work. Do not allow the vendor to claim that these documents are proprietary and that you, the purchaser, are not entitled to them. Place the vendor under contractual obligation to supply all agreed-upon documents in a pre-determined time frame and make clear that you will withhold 10 or 15 percent of the total purchase price until all contractual data transmittal requirements have been met.
- Contractually arrange for access to a factory contact on critical orders. Alternatively, insist on the nomination of a "management sponsor," which is a vice president, director of manufacturing, or a person holding a similar job function at the manufacturer’s facility or head offices. You should communicate with this person for redress on issues that could cause impaired quality or delayed delivery.
Following these guidelines will give best assurance of meeting the expectations of reliability-focused owner/purchasers.
WIN OR LOSE—IT’S ALWAYS THE PURCHASER’S CHOICE
January 2013 marked the 36th anniversary of an article on "Eliminating Cooling Water from General Purpose Pumps and Drivers"5. The article documented why many of the world’s largest refineries had discontinued using cooling water on pump bearings in the early and mid-1970s. There were also comprehensive write-ups dealing with cooling water elimination from pumps in the 1982, 1988 and 1998 editions of the book, "Improving Machinery Reliability"1. Working closely with only the three or four most knowledgeable pump manufacturers might have brought to light why the world’s most profitable pump users had deleted cooling water from pumps in the 1960s and early 1970s.
Which leads us to Case 1: Why are the uninformed still using cooling water on pumps?
This question was prompted by a recent visit to a midsize refinery in the United States. As of 2007, the facility continued to use cooling water on hundreds of pumps. The state government pointed out that the refinery’s water use placed much stress on a scenic river. Indeed, the refinery could have gained environmental compliance and greatly extended bearing lives much sooner. It could have deleted cooling water from process pumps years ago. In case you’re wondering, the basis for deleting cooling water from pump bearing housings equipped with rolling element bearings is found in the immutable laws of physics. Placing a cooling water jacket around a bearing’s outer ring will prevent it from thermally expanding. As the hot inner ring grows and the internal bearing clearances vanish, the bearing is excessively preloaded and fails prematurely. Or, if cooling coils are provided in the oil sump and the cooling water is indeed cold, some of the water vapor in the moist air floating above the oil will condense. The oil then becomes contaminated with water, which has much lower film strength than oil, so the bearings will fail prematurely.
Over the past three decades, this refinery probably spent a small fortune on avoidable pump repairs. It no doubt consumed hundreds of thousands of gallons of cooling water unnecessarily and, for a certainty, used more energy than was really necessary. That’s food for thought, especially since the facility’s pump repair frequencies were inferior to those typically seen at best-of-class pump user companies. The refinery is certainly the loser here and we’ll leave it to the reader to decide where the problem originates. (Hint: Dig deep and peel off the many layers of indifference.) Again, working with three or even four knowledgeable pump manufacturers would increase the probability of becoming acquainted with these facts.
Here’s a second, similarly relevant case history: Upgrading is the customer’s job.
A major manufacturer of very thoughtfully engineered upgrade components for pumps sent two of its managers to explain these superior upgrade products to a well-known pump manufacturer. After carefully laying out why reliability-focused users have implemented pump upgrades using the components at issue, the managers concluded that:
“Pursuing the OEM avenue, i.e., convincing the pump manufacturers of the merits of upgrading their pumps, is not possible. For some time now, the technical sales approach does not seem to work with U.S. pump manufacturers. By any measure, they only want to cut the cost, not improve quality. We determined that the only way many U.S. pump manufacturers will listen is if their end-customers demand our superior upgrade components on new equipment. We are convinced that we must begin with selling to the end-customers first.”
The attitude displayed by original equipment manufacturers (OEMs) shouldn’t surprise us at all. This experience is not new and an article by Joe Askew6 is among many publications that fully support the same findings. The article prompted the following comment from a technical editor in the United Kingdom:
“It's all about cost and widespread ignorance of how inefficient some systems are. What makes it so tragic is the terrible waste of energy and the consequences of that waste. Europe has experienced one of its hottest and most uncomfortable summers to date (2012). It's only when plants appreciate the missed opportunities and cost savings inherent in energy conservation that they will be motivated to take real steps to install and run their systems efficiently.”
Again, it’s up to the equipment user to demand better performance. Surely, a solid and well detailed user specification that includes upgrade measures implemented by best practices companies would do wonders here. And unless a corporation or facility has such a specification, the kind of narrow focused and repair intensive response one gets from many pump manufacturers will be perpetuated. Dealing with three or four highly competent manufacturers will be of benefit. At least it makes an attempt to move the reliability focus along. In contrast, single sourcing is a reward for low pricing and all too often slows down the process of innovation.
A third case history was excerpted from an e-mail contributed by an observant engineer. He concluded: OEMs want your spare parts business:
“One of our designers was recently meeting with a major client, his engineering company and a major manufacturer of lobe blowers in Europe. Both the owner and the engineering company wanted pure oil mist on the bearing end and purge mist on the timing gear end of the blower. The manufacturer refused to approve pure oil mist and would not give warranty coverage. What is more interesting is that he told everybody the reason why. He said he would not be able to sell as many bearings and parts if he allowed the installation of pure oil mist.”
That, too, is not surprising. When bid invitations for a major petrochemical facility in Texas were sent to a number of pump manufacturers in 1976, three potential pump vendors replied that they could not accept warranty responsibilities for the several hundred pumps they proposed to furnish for this project. These pumps were to be provided with pure oil mist. No constant level lubricators and troublesome oil rings were involved. Not to be fooled, the user-purchaser responded by standing up to the three pump manufacturers. Each was notified that they would be released from all responsibilities affecting bearing performance and bearing life. However, if they would not accept all customary responsibilities for the hydraulic performance of their products, they would be disqualified from supplying pumps for this project and all future jobs requiring pure oil mist on pump bearings.
The three vendors then quickly agreed to give warranties on the hydraulic ends of their pumps. Every one of their pumps was still in service almost four decades later, although none of these three “legacy” pump manufacturers still exist today. Lack of innovation was probably among the factors hastening their demise.
SINGLE SOURCING COMPRESSORS?
Suppose you have good experience with Compressor Manufacturer X, but the oil-free piston design of “X” incorporates piston rings and rider bands that, of course, are contacting the cylinder bore. A measure of wear will take place and parts need to be replaced in certain intervals. Compressor Manufacturer Y makes labyrinth piston compressors (Figure 1) that require fewer parts replacements and thus have higher availability. Regrettably, your project engineers and reliability professionals know little if anything about “Y.” Understandably, Manufacturer Y rarely sees fit to spend time educating owner-purchasers who make it a habit to buy only from technologically challenged Manufacturer X.
Figure 1: Labyrinth piston compressor principles (Illustration courtesy of Burckhardt Compression, Winterthur, Switzerland)
A similar argument could be made for liquid-flooded twin screw compressors (Figure 2) from Manufacturer A. Many design contractors and even single source provider “A” think that wet screw compression means that oil flooding is used in twin screw positive displacement machines. The single source provider has little or no incentive to tell others that Competitor B makes big and small twin screw compressors that are water- flooded. Science tells us that water removes far more heat from a compressed gas than a charge of oil. That “B” could have done the job in a single compressor housing was not known to you and after “A” happily sold you two compressor casings in series, “B” considers it a waste of time to submit bids to fulfill any of your future business needs. The same goes for integrally geared compressors, where some vendors have experience with four stages, while others may have provided as many as 10 stages of compression. Again, making two or three different vendors your technology providers can be essential for present and future success.
Figure 2: Wet screw compressor (7000 hp, water-flooded) at assembly. (Photo courtesy of Aerzener Maschinenfabrik, Aerzen/Germany and Aerzen USA, Kulpsville/PA)
Here’s another issue: Are your reliability engineers willing to do what others did 40 and 50 years ago, that is to understand the immense value of intelligent lubrication technology and take a stand for it? If the answer is in the affirmative, we commend you. If it is negative, we encourage you to ask a few questions and include the most important ones: What are you planning to do about a lack of understanding in your organization? Which vendors have you identified as capable advocates of sound technologies and innovation? How do you best include them in your list of technology providers?
The owner-purchaser must become educated. Unless owner-purchasers insist on quality, they will likely and inadvertently buy maintenance or repair-intensive products. More often than not, the user will then be at the mercy of a single source supplier. Relying on feedback or input from a single design contractor or a single equipment manufacturer is rarely sufficient. In the final analysis, the buyer gets what he or she deserves. It will be either more downtime risk and bloated maintenance budgets or higher long-term equipment reliability and profitability. And let us not forget the imputed value of educating a whole generation of reliability engineers. While often overlooked, the educational benefits of dealing with more than one supplier deserve to be considered.
The choice is clearly up to the owner-purchaser. As of today, no petrochemical or oil refining company that I know of has reached best-inclass status while single sourcing important equipment and components. Hopefully, this two-part sequence of articles has revealed some of the reasons why.
- Bloch, Heinz P. Improving Machinery Reliability, 3rd Edition. Houston: Gulf Publishing Company, 1998.
- Bloch, Heinz P. and Budris, Allan R. Pump User’s Handbook: Life Extension, 3rd Edition. Lilburn: Fairmont Publishing Company, 2010.
- Bloch, Heinz P. Practical Lubrication for Industrial Facilities, 2nd Edition. Lilburn: Fairmont Publishing Company, 2009.
- Bloch, Heinz P. Pump Wisdom: Problem Solving for Operators and Specialists. Hoboken: John Wiley & Sons, 2011.
- Bloch, Heinz P. Eliminating Cooling Water from General Purpose Pumps and Drivers. “Hydrocarbon Processing,” January 1977.
- Askew, Joe. Tales of an Engineering Consultant, World Pumps. “ScienceDirect,” June 2006.
Heinz P. Bloch is a consulting engineer and ASME Life Fellow with over 50 years of industrial experience. He advises process plants worldwide on maintenance cost reduction and reliability upgrade issues. Many of his 18 textbooks on reliability improvement subjects are completely uptodate or leading edge. They can be obtained from the MRO Bookstore or from Amazon.com.